Why Drug Test Results Come Back Invalid or Inconclusive

One thing that occurs during test is results may come back invalid or inconclusive. An invalid or inconclusive does not usually equal positive or a failed test. The means test was inconclusive while performing the test. There is various reasons why this could occur such as:

  • Their tests could of either defective or their equipment is faulty
  • Equipment is not calibrated correctly
  • Unidentified adulterant or an unidentified interfering substance
  • Lack or Urea
  • The sample was not suitable for testing
  • GC/MS interference
  • Immunoassay interference

We once had an issue with a large amount of our urine samples having unusually high pH, we eventually discovered after tracking the chain of custody that the delivery company transporting samples had faulty storage when transporting the samples. Unfortunately with companies trying to lower cost and maximize profits a lot of invalid are occurring because labs are cutting corners or not following protocols correctly to please management. This has led to honest drug free people having their results come back invalid or not consistent with human urine because of this. The MRO’s may attempt to figure what what caused this, but that is not cost effective either. ¬†Usually it’s up to the employer on how they want to handle the results.

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